Passionate about Linux hardening, compliance, security management and new technologies.

Why we use your open source project (or not)

Common mistakes in open source software projects While ‘shopping’ for some libraries, it struck me how many open source software projects are suffering from basic mistakes. Well, mistakes might sound too harsh. What I mean are those things you find on a project, which could be better. They are usually things not considered by the developer, as we (developers) were never told about them. Doing 10+ years of open source development now, I can safely say I made many mistakes. Time to […]

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How to see the version of Oracle Linux

Determine Oracle Linux version Oracle Linux is based on Red Hat Enterprise Linux. At first, it may be confusing to determine what specific operating system is running. This is because both have the /etc/redhat-release file. If that file exists, use the cat command to display the contents. Next step is to determine if there is a /etc/oracle-release file as well. If so, then you can be sure that Oracle Linux is running. cat /etc/oracle-release Sample output might be: Oracle Linux Server release […]

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Ubuntu Server Hardening Guide: Quick and Secure

Ubuntu hardening for servers and desktops The system hardening process of a server is critical during and after installation. It helps the system to perform its duties properly and stay secured as much as possible. This blog post about Ubuntu system hardening will look into the most critical steps to take first. More detailed system hardening steps can be added on top of these, for which we will share some tools and guides at the end. As most security guides […]

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Show vulnerable packages on Arch Linux with arch-audit

Vulnerable Software Packages on Arch Linux Vulnerabilities happen and are usually fairly quickly fixed. This is also true for Arch Linux. This rolling distribution can be considered to be always up-to-date, as it uses the latest versions of software packages from the upstream. When there is an update, it doesn’t take long that it becomes available and can be installed with package manager pacman. One problem that remained was the inability to quickly test if you have any vulnerable packages. After all […]

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Linux Security Guide (extended version)

Linux Security Guide (extended version) With so many articles about Linux security on the internet, you may feel overwhelmed by how to properly secure your Linux systems. With this guide, we walk through different steps, tools, and resources. The main goal is to have you make an educated choice on what security defenses to implement on Linux. For this reason, this article won’t show any specific configuration values, as it would implicate a possible best value. Instead, related articles and […]

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Discover to which package a file belongs to

Related Packages and Files Sometimes you want to know the related package of a file, before installation, or when it is already there. This is of great help during system hardening or general system cleanups. In this article we have a look at several ways to determine the relationships between files and the package they belong to. We have gathered this information for multiple Linux distributions. CentOS, Fedora, RHEL Show files for RPM packages rpm -qlp /path/to/file.rpm Show files for packages on […]

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More love for infosec defenders

Infosec defenders are a rare breed Most security conferences focus on the offensive side of security. Recently O’Reilly decided to change things a bit and come with a conference focused on defensive security. If you ask us, a great step to give defense a boost in attention. As O’Reilly is also focusing on open source, a perfect match with our audience. Disclaimer: we have no affiliation with O’Reilly, their conference, or services. We promote them as they increase knowledge sharing. Conferences […]

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Examples for daily usage of the grep command

Using the Grep command by example The grep command is one of the oldest tools for Linux and other platforms. Actually, it is much older than Linux, as is written by Ken Thompson more than 40 years ago. The name grep stands for “globally regular expression print”. This name comes from its predecessor ed and the specific mode in which you would globally search, using a regular expression, and print the output. The related command was “g/re/p”. Enough history, it is […]

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